WO2018010878A1

WO2018010878A1 - Power plant having optimized preheating of feed water for deep erected turbine sets

Info

Publication number: WO2018010878A1
Application number: PCT/EP2017/062130
Authority: WO
Inventors: Carsten Graeber
Original assignee: Siemens Aktiengesellschaft
Priority date: 2016-07-11
Filing date: 2017-05-19
Publication date: 2018-01-18
Also published as: DE102016214960B3

Abstract

The invention relates to a power plant (1) having a water-steam circuit (2), wherein in the water-steam-circuit (2) at least one low-pressure preheater (3), a steam generator (6), a steam turbine (7), a capacitor (8), and a feed water pump (9) are connected. The feed water pump (9) can be driven by a feedwater pump drive turbine (11) by way of a shaft (10). According to the invention, a steam line (12) is provided, via which the feedwater pump drive turbine (11) is connected to the low-pressure preheater (3) such that steam from the feedwater pump driving turbine (11) can be fed to the low-pressure preheater (3).

Description

description

Power plant with optimized preheating of feed water for low-level turbo sets

When using steam turbines in power plants, the type of installation of the turbo set is an essential condition for the plant design and thus for the costs incurred. As turbo set is generally understood the arrangement how turbines and generator are arranged on a common shaft.

The turbo set can be arranged in a so-called low position, which in recent years has mainly been used for combined cycle gas turbine (GUD) applications. In low-set turbo sets, the condenser is placed next to the steam turbine. A high position towards ^¬ , finds predominantly in pure steam turbine plants application, which have a capacity of 250 MW or more. For high-set turbo sets can capacitor arranged for space reasons below the steam turbine.

The low setting offers special advantages, since the reduction of the installation height can result in more cost-effective project planning and erection of the machine house. The disadvantage, however, is that just the required for a regenerative preheating large number of taps on the steam turbine housing can be implemented very difficult constructive. Therefore, especially for larger steam power plants having a plurality of taps on the steam turbine housing, the high position of the turbo set constructively advantageous because an arrangement of the nozzle and the derivation of the pipeline due to the installation height (centerline) is possible ^¬ .

By the many bleed steam lines, which it from a

Steam turbine housing is to be diverted, is a transfer of the thermodynamic design of the turbo set and the ent did not just make it as easy as moving technologies from a high-mounted turbo set to a low-set turbo set. A thermodynamically designed high-altitude turbo set can therefore not be placed low, but always requires its own design. Since the arrangement of the taps, especially in the low pressure range, is made difficult by the low position, in the past only turbo sets for the low position with a small number of tapping options have been developed, which does not represent the optimum thermodynamic.

In current high-altitude power plant concepts usually three taps are led out of the steam turbine. With comparable deep-set power plant concepts only two taps are possible. This means that at entspre ^¬ sponding deeply established power plant concepts lack at least one tap. Usually, the thermodynamic influence of an additional tap in the low pressure steam region on the cycle efficiency is manageable. However, as the mini- nimale pressure level of the first tap may be limited in deep erected turbine generators, the negative efficiency effects can be in the significant range of> 0.6%, and thus represents a major inconvenience to deep set ^¬ presented turbine sets.

Object of the invention is therefore to admit a power plant at ^¬ which is on the one hand for the cost Tiefauf ^¬ position, so lowered Centerline, but requires fewer taps of the low-pressure part of the steam turbine, which while not significantly nega ^¬ tive thermodynamic effect , It is another object of the invention to provide a corresponding method.

The object relating to a power plant object of the inventions is dung achieved by a power plant, with a What ^¬ ser-steam circuit, wherein in the water-steam circuit min ^¬ least a low-pressure, a steam generator, a steam turbine, a condenser and a Feedwater pump with the feedwater pump via a shaft from a feedwater pump drive turbine (SPAT)

is drivable. According to the invention is ^pre-¬ see a steam line, via which the feed water pump drive turbine is connected to the low-pressure, so that vapor from the feed water pump drive turbine is fed to the low pressure economizer. Thus, a portion of the regenerative preheating in the important low-temperature range can be acquired by <100 ° C by the inventive steam ^¬ line.

The invention is based on the consideration not to lead the steam from the feed pump drive turbine on the Kondensa ^¬ tor but to use the Niederdruckvorwärmung. Since the feed pump drive turbine is supplied with higher-value steam from the medium-pressure part of the steam turbine, thereby a tapping of the low-pressure part of the steam turbine for the low-pressure preheating can be omitted. Through an optimized integration of the steam of the feed pump drive turbine in the additional low-pressure preheater thermodynamic see the disadvantage of otherwise missing Niedertemperaturvorwärumg to 100 ° C is almost completely compensated.

It is advantageous in particular that the exhaust steam of a commonly used feed pump drive turbine is clearly above the otherwise relevant condenser pressure. This fact can be used to carry the feed pump drive ^¬ turbine due to significantly reduced volume throughputs kos ^¬ tengünstiger. In a preferred embodiment of the invention is the

Steam line connected to a tapping point on the feedwater pump drive turbine, which is arranged between ^¬ steam inlet and the steam outlet of the feedwater pump drive turbine, so that the Niederdruckvorwärmer steam from the tapping point of the feedwater pump drive turbine can be fed. By selecting the tapping point of the feedwater pump drive turbine, a corresponding steam can be removed, with its steam parameters to the requirements of Low pressure preheater corresponds. As a result, a higher flexibility between the fulfillment of the requirements of the feedwater pump and the preheating section in the design point can be achieved. The additional tapping takes place at a specially designated point of the feedwater pump turbine, which corresponds to neither the steam inlet nor the steam outlet. Since ^¬ can be controlled by the low-pressure specific higher-quality steam can be supplied. Furthermore, this ensures that both the requirements of the feedwater pump at subcritical (steam pressures <200 bar) and supercritical systems (steam pressures> 230 bar) are met, as well as an optimal integration of the steam in the

Low pressure preheating can be done. This additional supply of steam can be designed so thermodynamically that in special load cases, for example in case of failure of the low pressure preheater, the feedwater pump drive turbine can be operated without restrictions. Alternatively, the steam line can be arranged at the steam outlet of the feedwater pump drive turbine, so that the low pressure preheater Abdampf from the tapping point of the feedwater pump drive turbine can be fed. This configuration relaxes the steam in the feed water pump power turbine and only the exhaust steam becomes

Low pressure preheating used. Depending on the design of the power plant, this configuration can be advantageous.

In an advantageous further development of the power plant, a bypass line is furthermore provided, via which the feedwater pump drive turbine is connected to the condenser, so that in the event of a fault, steam from the feedwater pump drive turbine can be supplied to the condenser. The bypass line connects the feedwater pump turbine to the condenser. By an alternative steam route to the condenser ^¬ tor is thus ensured even in case of failure or in special Betriebszu- states that the steam from the feedwater pump turbine can be derived via a steam line. In order to obtain a higher flexibility in the load behavior of the plant, for many years the so-called

Condensate accumulation established. The main condensate is accumulated in the hotwell of the condenser. The feed water for the supply of the steam generator is removed from the storage contents of the feed water tank. The reduction of the main condensate quantity leads to a reduction in the low-pressure bleed-off mass flows and, associated therewith, to an increase in output in the turbo set, since the bleed steam that has not been removed can be expanded to condenser pressure. Since the first low-pressure preheater condenses the steam from the feed-water pump drive turbine and thus is needed to generate the power of the drive turbine, it must be reduced

Flow through the preheater in Kondensatstaubetrieb an al ^¬ ternative route of the steam in the drive turbine in Rich ^¬ tion of the capacitor be possible. The supply of storage sewasserpumpenturbine from the main steam turbine may in ^¬ dependence from the power demand of the feedwater pump (subcritical or supercritical) carried by the intermediate-pressure exhaust steam or the first medium pressure tap.

In the bypass line, a quick-opening valve (control valve) can be switched, which is opened in case of failure. This valve increases the operational flexibility and safety of the power plant.

Preferably, the bypass line is connected to the tapping point on the feedwater pump drive turbine. As a result, the operational flexibility can be increased further, since a higher flexibility between the fulfillment of the requirements of the feedwater pump and the preheating section can be achieved, and at the same time can be reacted to incidents. Alternatively, depending on the configuration of the power plant, it may also be advantageous if the bypass line is connected to the steam outlet at the feedwater pump drive turbine is. Depending on the design of the power plant, this configuration can also be advantageous.

Preferably, the steam turbine of at least one high-pressure part, to at least one medium-pressure part and Minim ^¬ least one low-pressure part. The feedwater pump drive turbine is connected via a Hauptanzapfdampfleitung with steam from at least one medium-pressure part of ^{Dampftur ¬} bine, wherein in the Hauptanzapfdampfleitung a control valve is connected, whereby steam in dependence on the power requirement of the feedwater pump drive turbine and / or the Niederdruckvorwärmers is controllable. Through the control valve a higher flexibility between the fulfillment of the requirements placed ^¬ the feedwater pump and the preheating is achieved route. Thus, controlled depending on the requirement of the Leis ^¬ tung Niederdruckvorwärmers and / or the tap of the feed water pump drive turbine steam ^¬ the. Alternatively, depending on the requirements of the power plant, it may also be advantageous if the feedwater pump drive turbine is connected to steam from at least one medium pressure section of the steam turbine via an exhaust steam line, wherein a control valve is connected in the exhaust steam line, through which steam as a function of the power requirement of the feedwater pumps -Atrieb drive turbine and / or the low ^¬ pressure preheater is regulated.

In a further expedient embodiment of the power plant, the low-pressure preheater comprises a connection for a condensate drain. Besides, one is

Condensate drain line provided by which the connection for condensate is connected to the main condensate line of the water-steam circuit. By this configuration, the condensate can be discharged from the low-pressure preheater, and introduced at a suitable position in the main condensate line. Preferably, the low pressure preheater constitutes a first low pressure preheater. The water / steam cycle further comprises a second low pressure preheater and a third low pressure preheater. The second low-pressure preheater in this case comprises a connection for a condensate drain, and also the third low-pressure preheater comprises a connection for a condensate drain. Furthermore, a

Condensate drain line provided by which the two connections for condensate ver ^¬ connected with the water-steam cycle, so drain condensate from the second low ^¬ pressure preheater and the third Niederdruckvorwärmer

mixable and the water-steam cycle is traceable.

It is advantageous if the condensate drain line is connected to the main condensate line of the water-steam cycle. Thereby, the condensate can be introduced at a suitable location in the main condensate line, whereby the condenser is relieved.

Alternatively, the condensate drain line may be connected to the first low pressure preheater of the water-steam cycle. Depending on the design of the power plant, this configuration can also be advantageous.

The invention is particularly directed to Kraftwerksanla ^¬ gene, which are configured as a steam turbine plant (DKW).

The on a method for operating a power plant ge ^¬ taught object of the invention is achieved by a method with a water-steam circuit, wherein in the water-steam circuit, at least one low-pressure, a steam generator, a steam turbine, a condenser and a feed ^¬ Water pump are connected, wherein the feedwater pump via a shaft of a feedwater pump drive turbine ^{¬ is} driven, wherein steam from the feedwater pump drive turbine via a steam line is fed to the low-pressure preheater. The inventive advantages of the method and the ent ^¬ speaking dependent claims are analogous to the advantages of the power plant according to the invention. In an advantageous further development of the method, the steam is taken either from a tapping point on the feedwater pump drive turbine which occurs between Dampfein ^¬ occurs and the steam outlet of the feedwater pump drive ^¬ turbine is arranged, or in the form of Abdampf from the steam outlet of the feedwater pump drive turbine.

In an advantageous further development, steam is supplied to the condenser via a bypass line from the feedwater pump drive turbine in the event of a fault, the steam being supplied either from the tapping point or at the steam outlet at the

Feedwater pump drive turbine is removed. The steam ^¬ removal from the extraction point is this the preferred Va ^¬ riante. Depending on the design of the power plant and the removal of waste steam may be advantageous. For example, if no tap on the feedwater pump drive turbine is possible or wanted.

Preferably, the steam turbine of at least one high-pressure part, to at least one medium-pressure part and Minim ^¬ least one low-pressure part. The feedwater pump drive turbine is supplied either via a Hauptanzapf ^¬ steam line with steam from at least one medium-pressure part of the steam turbine, or via an exhaust steam line with exhaust steam from at least one medium-pressure part of Dampfturbi ^¬ ne. A control valve it is switched to the Hauptanzapfdampfleitung or exhaust steam, whereby steam is controlled in depen ^¬ dependence of the performance requirement of Speisewasserpumpen- drive turbine and / or the Niederdruckvorwärmers.

In an advantageous further development of the method, condensate from the low-pressure preheater via a connection for condensate discharge through a condensate drain line in the main condensate line of the water-steam cycle.

Advantageously, the low-pressure economizer is designed as a low-pressure ers ^¬ ter, wherein the water-steam circuit further comprises a second low-pressure and a third low-pressure. Outflow condensate from the second low-pressure preheater is discharged at a connection for condensate drain, and drain condensate from the third low-pressure preheater is discharged at a connection for a further condensate drain. By a condensate drain line these two condensate drains are mixed, and the mixed drain condensate in the

Returned main condensate or in the first low-pressure preheater of the water-steam cycle.

Exemplary embodiments of the invention will be explained in more detail below with reference to FIGS. Show it:

Figure 1 is a schematic representation of a power plant with a high-altitude turbo set according to the prior art;

Figure 2 is a schematic representation of a power plant with a low-set turbo set according to the prior art;

Figure 3 is a schematic representation of a power plant with a low-set turbo set with a steam line through which the feedwater pump drive turbine is connected to the low-pressure preheater according to the invention;

Figure 4 is a schematic representation of a power plant with a low-set turbo set, further developed with a bypass line through which the feedwater pump drive turbine with the condenser ver ^¬ is connected; Figure 5 is a schematic representation of a power plant with a low-set turbo set according to a further development of the invention, wherein the steam line is connected to a tapping point on the feedwater pump drive turbine;

Figure 6 is a schematic representation of a power plant with a low-set turbo set according to a further development of the invention, wherein a

Condensate drain line 25 is provided, through which drain condensate from the connection for a condensate drain 24 from the first Niederdruckvorwärmer 27 of the main condensate line 26 of the water-steam cycle 2 can be fed;

Figure 7 is a schematic representation of a power plant with a low-set turbo set according to a further development of the invention, wherein a

Condensate drain line 34 is provided by which drain condensate from a second and third

Low pressure preheater and the third low-pressure preheater mixable and the first low-pressure preheater is traceable; Figure 8 is a schematic representation of a power plant with a low-set turbo set according to a further development of the invention, wherein a

Condensate drain line is provided, through which drain condensate from a second and third low-pressure preheater and the third Niederdruckvorwärmer mixable and the main condensate line is traceable;

FIG. 9 shows a schematic representation of a power plant with a low-set turbine set, according to a further development of FIG. 4, with a plurality of steam lines, via which the feedwater pump Drive turbine is connected to various Niederdruckvorwärmern.

1 shows a simplified schematic representation of a power plant 1 with a high-altitude turbo set according to the prior art.

Shown is a water-steam cycle 2, in which a low ^¬ pressure preheater 3, a steam generator 6, a steam turbine 7, a condenser 8 and a feedwater pump 9 are connected. In the water-steam circuit 2, a not illustrated ^¬ set condensate pump is connected. The steam turbine in this example consists of a combined high pressure part 17, medium pressure part 18 and a separate low pressure part 19. The steam turbine 7 is connected via a common shaft with a generator G.

The feedwater pump 9 is connected via a further shaft 10 to a feedwater pump drive turbine 11. The steam turbine 7 is removed at the middle pressure part 18 at a tapping point ^¬ steam, and fed via a bleed steam line 22 of the feedwater pump drive turbine 11. For tapping vapor line a tapping point on the central pressure part 18 of the steam turbine 7 is required. In the Anzapfdampf- line 22, a control valve 23 is connected, with which the extracted steam can be controlled depending on the required amount of steam. In the feedwater pump drive turbine 11, the steam is expanded, and the feedwater pump 9 is driven via the shaft 10 via the force arising ^therefrom . The expanded steam is supplied via a Dampflei ^¬ tung the capacitor. 8 The water-steam cycle 2 is essentially formed between the condenser 8 and the feedwater turbine 9 through a main condensate line 26.

If the turbo set is set up high, the condenser 8 can be arranged below the turbo set. Also, it can easily connect to multiple taps from the low pressure part 19 of the steam turbine 7 steam for the low-pressure preheater 3 are removed. In the example of FIG. 1, three low-pressure preheaters 3 are provided, which are supplied with steam from the low-pressure part 19 of the steam turbine 7. A first low-pressure preheater 27, a second low-pressure preheater 28 and a third low-pressure preheater 29 are also shown. A fourth low-pressure preheater 34 is also shown, which, however, is supplied with steam from the medium-pressure stage 18. Not ge ^¬ shows are further Hochdruckvorwärmer.

As will be demonstrated below using the example of FIG. 2, it is possible to accommodate less low-pressure preheater 3 in the case of a low-set turbine set due to the design.

FIG. 2 shows a simplified schematic representation of a power plant 1 with a deep-set turbo set according to the prior art. In the case of low-set turbo sets, the condenser 8 is structurally located next to the steam turbine 7. This requires, on the one hand, longer ^lineweighing from the low-pressure part 19 of the steam turbine 7 to the condenser 8. On the other hand, the low setting of the

Turbosatzes fewer taps to the low pressure part 19 of the steam turbine 7 connect.

Figure 2 shows a comparable water-steam circuit 2 as described in Figure 1, but can be through the

In low position, connect only two low-pressure preheaters 3 to the low-pressure turbine 19. Showing a first Never ^¬ derdruckvorwärmer 27 and a second low-pressure economizer 28, which are each connected via a steam line to the low-pressure section 19 of the steam turbine. 7 Shown is also a fourth Niederdruckvorwärmer 34, which is connected to the medium-pressure part 18 of the steam turbine 7. A third low-pressure preheater 29 can not be accommodated in the deep-set concept shown here.

Figure 3 shows a schematic representation of a power plant 1 with a low-set turbo set with a steam line 12, via which the feedwater pump drive turbine 11 is connected to the low-pressure preheater 3 according to the invention. Figure 3 differs in particular from the prior art in Figure 2, that at least one of Never ^¬ derdruckvorwärmer 3 vapor from the Speisewasserpumpen- power turbine is fed. 11 The low-pressure preheater 3 here symbolizes the first low-pressure preheater 27 from FIGS. 1 and 2. Not shown are further low-pressure ^preheaters , which are supplied with steam via the low-pressure part 19 of the steam turbine 7 and are arranged between the low-pressure preheater 3 and the feedwater pump 9.

The steam from the feedwater pump drive turbine 11 is not fed to the condenser 8 as in FIG. 1 or 2, but used for low pressure preheating. Furthermore, the feedwater pump drive turbine 11 is supplied via a Hauptanzapf ^¬ steam line 20 with higher-grade steam from the medium-pressure part 18 of the steam turbine 7. As a result, an Anzap ^¬ tion of the low-pressure part 19 of the steam turbine 7 for the

Low pressure preheating 3 omitted. In the Hauptanzapfdampf- line 20 is diverted from the exhaust steam of the medium-pressure part 18 of the steam turbine 7. In the Hauptanzapfdampfleitung 20, a control valve 21 is connected, through which the amount of steam which can be fed to the feedwater drive turbine 11, is controllable. Thanks to the optimized integration of the steam of the feed water pump drive turbine 11 in the additional low ^¬ druckvorwärmer 3 the thermodynamic disadvantage of the otherwise missing Niedertemperaturvorwärumg is almost completely compensated for to 100 ° C. The exhaust steam of a feedwater pump drive turbine 11 commonly used is well above the otherwise relevant ^¬ condenser pressure. This fact can be used to thus carry out the feed water pump drive turbine 11 due to interpreting ^¬ Lich reduced volume flow rates and less cost-effective.

By the control valve 21, which is connected in the Hauptanzapfdampflei ^¬ tion 20, steam is dependent on the Leis- Supply requirement of the feedwater pump drive turbine 11 and / or the low-pressure preheater 3 adjustable. By the Re ^¬ gelventil 21 can thus be the line of the feedwater drive turbine 11 or the Niederdruckvorwärmers 3 separated from each other, or regulate feedwater drive turbine 11 and 3 Niederdruckvorwärmers together.

FIG. 4 is based on the inventive concept of FIG. 3 and shows a schematic representation of a power plant 1 with an advanced deep-set turbine set with a bypass line 16, via which the feedwater pump drive turbine 11 is connected to the condenser 8.

Figure 4 also shows a water-steam cycle 2, in which a low-pressure preheater 3, a steam generator 6, a

Steam turbine 7, a condenser 8 and a feedwater pump 9 are connected. The steam turbine 7 also consists of a combined high-pressure part 17, medium-pressure part 18 and a separate low-pressure part 19.

The feed water pump 9 is connected via a ^¬ inde pendent of the turbine generator shaft 10 with a feed water pump drive turbine. 11 The steam turbine 7 is taken from the intermediate-pressure section 18 at a tapping point steam, and steam line over the Anzapf- 22 of the feed water pump drive turbine 11 out to ^¬. In the tapping steam line 22, a control valve 23 is connected. In the feed-water pump drive turbine 11 the steam is expanded, thereby driving the feed ^¬ water pump 9 via the shaft 10th The expanded steam is supplied via the steam line 12 to the first low-pressure preheater 27. The tap steam line 22 and the control valve 23 essentially correspond to the main tap steam line 20 and the control valve 21. The distinction has been made to make it clear that a tapping point on the medium pressure section 18 is required in the tap steam line 22. Alternatively, the main tapping steam line 20 and the control valve 21 of FIG. 3 may be provided. In the further development of the embodiment in FIG. 3, the bypass line 16 is connected to the steam line 12 in FIG. But the bypass line 16 can also be connected directly to the feedwater pump drive turbine 11 with the same effect. In the bypass line 16 to the condenser 8, a quick-opening valve (Re ^¬ gelarmatur) is connected to all relevant load conditions ( ^¬ including Störlastfällen) to be able to control. Figure 4 also shows a second low-pressure economizer 28 and a third low-pressure economizer 29, which will ensure 7 ver ^¬ with tapped steam from the low-pressure section 19 of the steam turbine. Furthermore, a fourth low-pressure preheater 34 can also be seen, which, however, is supplied with steam from the middle pressure part 18 of the steam turbine 7. The in the

Low pressure preheater introduced steam gives off heat at the respective point in the water-steam cycle 2 from. The resulting condensate is discharged from the respective low ^¬ pressure preheater. For this purpose, the fourth low-pressure preheater 34 comprises a connection for a condensate drain

35 can be fed through the drain condensate to the third low-pressure preheater 29. The third low-pressure preheater 29, in turn, comprises a connection for a condensate outlet 31 through which outflow condensate can be fed to the second low-pressure preheater 28. However, the second low-pressure preheater 28 includes a connection for a condensate drain 30 through the drain condensate of the main condensate line 26 is the water-steam cycle 2 is supplied. The drain condensate of the first low-pressure preheater 27 is connected via a

Condensate drain line 25 is returned to the condenser 8.

Further, in Figure 4 in the water-steam circuit 2 Zvi ^¬ rule of the feedwater pump 9 and the steam generator shown 6 more high-pressure preheater, the pressure part with steam from the high 17 and medium-pressure section 18 of the steam turbine is provided. FIG. 5 shows a schematic representation of a power plant with a low-set turbine set according to a further development of the invention, the steam line 12 being connected to a tapping point 13 on the feedwater pump drive turbine 11. Figure 5 corresponds in this case We ^¬ sentlichen the embodiment of Figure 4, but with the following differences:

In the embodiment of Figure 5, the feed water pump drive turbine 11 is supplied via the Hauptanzapfdampfleitung 20 with steam from the exhaust steam of the intermediate pressure section 18 of the steam turbine ^¬ 7 and not by bled steam. In addition, the steam line 12 is connected to a tapping point 13 on the feedwater pump drive turbine 11. The tapping point 13 is arranged between the steam inlet 14 and the steam outlet 15 of the feedwater pump drive turbine 11. The bypass line 16 is connected to the steam outlet 15.

Figure 6 shows a schematic representation of a power plant 1 with a low-set turbo set according to a further development of the invention, wherein the condensate drain line 25, the drain condensate from the first Niedruckvorwärmer 27 of the main condensate line 26 of the water-steam cycle 2 supplies. In the condensate drain line 25 may be connected another pump. In the exemplary embodiment in FIG. 6, the feedwater pump drive turbine 11 is supplied with steam via the main extraction steam line 20 from the medium-pressure part 18 of the steam turbine 7. The steam line 12 is concluded reasonable at An ^¬ tapping point 13 of the feed water pump drive turbine 11, the bypass line 16 15 steam outlet In contrast to Figure 5, the flow of condensate is not discharged into the capacitor 8 at a port for a condensate drain 24 of the first low-pressure economizer 27 but is connected via a condensate drain line 25, through which the connection for condensate drain 24 to the main condensate line 26 of the water-steam cycle 2 is connected. Figure 7 shows a further alternative or supplementary From ^¬ guide form a schematic representation of a power plant with a deep drawn up turbo set, a

Condensate drain line 34 is provided, through which effluent condensate from the second low-pressure preheater 28 and third low-pressure preheater 29 mixable and the first low-pressure preheater 27 is traceable.

Figure 8 shows a schematic representation of a power plant with a low-set turbo set according to a further development of the invention, wherein a condensate drain line is provided, through which drain condensate from a two ^¬ ten Niederdruckvorwärmer 28 and third Niederdruckvorwärmer 29 can be mixed and the Hauptkondensatleitung traceable. It is assumed that there are additional advantages for the system layout, if a part of Nie ^¬ derdruckvorwärmer be plugged into the machine capacitor. Inserted means that 1 or 2 low-pressure will not be placed in the nacelle, but di rectly ^¬ be accommodated in the capacitor with the advantage of very short steam pipes and a space saving. For this, however, it is necessary to observe a special version of the low-pressure preheater and the corresponding condensate drain. Figure 9 is a is a schematic illustration of a power plant with a deep ^¬ established turbo set, according to a further development of figure 4, wherein a plurality of steam lines are provided via which the Speisewasserpumpen- comparable power turbine with different Niederdruckvorwärmern is prevented. The arrangement shows a first low pressure preheater 27, a second low pressure preheater 28, a third low pressure preheater 29, and a fourth low pressure preheater 34. The feedwater pump drive turbine 11 has a flash point and a bleed point. The exhaust point is connected to the first low-pressure preheater 27 by a first steam line 12. The tapping point is connected to a second line 12 ^λ with a low pressure preheater downstream of the first low-pressure preheater 27 connected. In the example of FIG. 9, the downstream low pressure preheater is the second low pressure preheater 28.

The second low-pressure preheater 28 comprises a cooler with a connection for a condensate drain through the drain ^¬ condensate the first low-pressure preheater 27 can be fed. The main advantage of this design is that the steam lines 12 and 12 ^λ can be made compact, since the steam in the drive turbine not up

Condenser vapor pressure level and associated high from ^¬ steam flow rates must be relaxed.

Claims

claims

1. power plant (1) with a water-steam cycle (2), wherein in the water-steam cycle (2) at least one Niederdruckvorwärmer (3), a steam generator (6), a steam turbine (7), a capacitor ( 8) and a feedwater pump (9) are connected, wherein the feedwater pump (9) via ei ^¬ ne shaft (10) by a feedwater pump drive turbine (11) is drivable,

characterized in that

a steam line (12) is provided, via which the feedwater pump drive turbine (11) with the Niederdruckvor ^¬ warmer (3) is connected so that steam from the feedwater pump drive turbine (11) the low pressure preheater (3) can be supplied.

2. Power plant (1) according to claim 1,

characterized in that

the steam line (12) to a tapping point (13) on the feed water pump drive turbine (11) is connected between the steam inlet (14) and the steam outlet (15) of the feed water pump drive turbine (11) is arranged so ^¬ that the Low pressure preheater (3) steam from the tapping point (13) of the feedwater pump drive turbine (11) can be fed.

3. power plant (1) according to claim 1,

characterized in that

the steam line (12) is arranged on the steam outlet (15) of the feedwater pump drive turbine (11), so that exhaust steam from the tapping point (13) of the feedwater pump drive turbine (11) can be supplied to the low-pressure preheater (3).

4. Power plant (1) according to one of claims 1 to 3, characterized in that

Furthermore, a bypass line (16) is provided, via which the feedwater pump drive turbine (11) with the Kondensa ^¬ tor (8) is connected, so that in case of failure steam from the storage Sewasserpumpen drive turbine (11) to the capacitor (8) can be fed.

5. Power plant (1) according to claim 4,

characterized in that

the Bypassleiung (16) to the tapping point (13) at the feed ^¬ water pump drive turbine (11) is connected.

6. Power plant (1) according to claim 4,

characterized in that

the Bypassleiung (16) at the steam outlet (15) on the water pumps Speisewas ^¬-driving turbine (11) connected.

7. Power plant (1) according to one of claims 1 to 6, characterized in that

the steam turbine (7) comprises at least one high-pressure part (17), at least one medium-pressure part (18) and at least one low-pressure part (19), the feed-water pump drive turbine (11) being supplied with steam from at least one medium-pressure part (18) via a main extraction steam line (20) ) of the

Steam turbine (7) is connected, wherein in the Hauptanzapf ^¬ steam line (20), a control valve (21) is connected, where ^¬ controllable by steam as a function of the power requirement of the feedwater pump drive turbine (11) and / or the low-pressure preheater (3) is.

8. Power plant (1) according to one of claims 1 to 6, characterized in that

the steam turbine (7) consists of at least one high-pressure part (17), at least one medium-pressure part (18) and at least one low-pressure part (19), the feed-water pump drive turbine (11) being supplied with steam from at least one medium-pressure part (18) via a bleed steam line (22) ) the steam turbine ^¬ (7) is connected, wherein in the bleed steam line (22), a control valve (23) is connected, through which steam in

Dependence of the power requirement of the feedwater pump drive turbine (11) and / or the Niederdruckvorwärmers (3) is adjustable.

9. power plant (1) according to one of claims 1 to 8, characterized in that

the low pressure preheater (3) has a connection for a

Condensate drain (24) includes, and that a

Condensate drain line (25) is provided, through which the connection for condensate drain (24) with the

Main condensate line (26) of the water-steam circuit (2) is connected.

10. Power plant (1) according to one of claims 1 to 9, characterized in that

the low-pressure preheater (3) constitutes a first low-pressure preheater (27), and the water-steam circuit (2) further comprises a second low-pressure preheater (28) and a third low-pressure preheater (29), the second low-pressure preheater (28) having a connection for one

Condensate drain (30), and the third Niederdruckvor ^¬ warmer (29) comprises a connection for a condensate drain (31), and that a Kondensatablaufleitung (32) is provided, through which the two connections for condensate drain (30, 31) with the water Steam cycle (2) are connected so that drain condensate from the second low-pressure preheater (28) and the third low-pressure preheater (29) mixable and the water-steam cycle (2) is traceable.

11. Power plant (1) according to claim 10,

characterized in that

the condensate drain line (32) is connected to the main condensate line (26) of the water-steam cycle (2).

12. Power plant according to claim 10,

characterized in that

the condensate drain line (32) is connected to the first low-pressure preheater (27) of the water-steam cycle.

13. A method for operating a power plant (1) with ei ^¬ NEM water-steam cycle (2), wherein in the water-steam cycle (2) at least one Niederdruckvorwärmer (3), a Steam generator (6), a steam turbine (7), a condenser (8) and a feedwater pump (9) are connected, wherein the feedwater pump (9) via a shaft (10) by a feed ^¬ water pump drive turbine (11) is driven, wherein steam (4) from the feedwater pump drive turbine (11) is supplied via a steam line (12) to the low pressure preheater (3).

14. The method of claim 13, wherein either steam (3) from a tapping point (13) on the feedwater pump drive turbine (11) is removed, which occurs between Dampfein ^¬ (14) and the steam outlet (15) of the feedwater pump drive turbine (11 ) is arranged, or steam in the form of exhaust steam from the steam outlet (15) of the feedwater pump drive turbine (11) is removed.

15. The method of claim 13, wherein in case of failure steam via a bypass line (16) from the feedwater pump drive turbine (11) is supplied to the condenser (8), wherein the steam either from the tapping point (13) or on

Steam outlet (15) on the feedwater pump drive turbine (11) is removed.

16. The method according to any one of claims 13 to 15, wherein the steam turbine (7) consists of at least one high-pressure part (17), at least one medium-pressure part (18) and at least one low-pressure part (19), wherein the feedwater pump drive turbine (11) either via a main steaming line (20) is supplied with steam from at least one medium-pressure part (18) of the steam turbine (7), or is supplied with exhaust steam from at least one medium-pressure part (18) of the steam turbine (7) via an exhaust steam line (22), wherein in the main ^¬ tap steam line (20) a control valve (21) or in the exhaust steam line (22) is connected a control valve (23), whereby steam in dependence of the power requirement of

Feedwater pump drive turbine (11) and / or the low ^¬ pressure preheater (3) is controlled.

17. The method according to any one of claims 13 to 16, wherein condensate (33) from the Niederdruckvorwärmer (3) via a connection for condensate drain (24) by a

Condensate drain line (25) in the main condensate line (26) of the water-steam cycle (2) is passed.

18. The method according to claim 13, wherein the low-pressure preheater (3) constitutes a first low-pressure preheater (27), wherein the water-steam cycle (2) continues to ^supply a second low-pressure preheater (28) and a third low-pressure preheater (29 ), wherein drain condensate from the second Niederdruckvorwärmer (28) at a connection for condensate drain (30), and drain condensate from the third Niederdruckvorwärmer (29) at a connection for a

Condensate drain (31) are mixed by a Kondensatablaufleitung (32), and the mixed drain condensate in the main condensate line (26) or in the first Niederdruckvorwärmer (27) of the water-steam cycle (2) is returned.